Building materials with metal may serve as electromagnetic shields and deteriorate the transmissions of wireless LAN in residences. To improve the transmissions at a low cost, a conducting wire processed as an inverted-L antenna is attached to a very small hole in the electromagnetic shield. The optimal shape of the conducting wire was found to be 10 mm vertically from the mounting surface and 25 mm at right angles from its tip, as well as its characteristics as an antenna. In addition, the guideline for the installation location based on this experimental result can be considered.
This paper proposes a nonparametric Bayesian updating method for nonlinear seismic response analysis models considering uncertainties using Variational Auto-Encoder (VAE). The proposed method is used for calculating the likelihood of the parameters for the response analysis model using VAE without any assumptions about the probability distribution. The proposed method is confirmed to successfully update the probability distribution of the parameters of a bilinear single-degree-of-freedom system. To discuss the characteristics of the proposed method, the relationship between the uncertainty due to the lack of information on the nonlinear response and the width of the posterior distribution of the parameters is investigated.
Rupture directions of 17 northwestern Chiba prefecture earthquakes with Mw3.8-5.9 are estimated assuming the unilateral rupture using azimuth-dependency of apparent source spectral ratios. Rupture directions of at least near 1/3 of earthquakes have frequency-dependency. This result can be interpreted that different-sized strong motion generation areas are located at the different directions from the hypocenter. The largest two repeating earthquakes with Mw5.9 are estimated to have the same stress drop, but they ruptured to different direction each other and the directions have frequency-dependency. Ground motions within 100 km of most of earthquakes have rupture directivity effects up to 10Hz.
As second shape factor of rubber bearings is small, buckling strain is decrease. In this study, new flare-like structure in order to improve buckling property is proposed. In the conventional structure of rubber bearings, outer diameter of inner rubber is uniform for all layers. In the proposed flare-like structure, outer diameter is not uniform and the diameter of upper and lower layer is larger than that of center layer. First, outline of flare-like structure is introduced. Second, improvement of ultimate properties by flare-like structure is proved theoretically. Third, buckling properties improvement is proved based on finite element analysis.
The present study presents a new FEM element for buckling analysis of T-section members as well as H-section and its application to spatial structures. The element is fundamentally composed of parallel three beams together with two struts normal to the three elements, enabling a consideration of lateral-torsional buckling. The present study first investigates the capability to analyze buckling strength of T-sections, extended to H-sections with different sizes for top and bottom flanges, then, followed by buckling analysis to a shallow arch. Through the analyses, the effectiveness of the proposed element for buckling analysis of spatial structures is confirmed.
Stadium roofs generally require a large opening in the center, and in recent years a roof structure consisting of radially arranged cables has been used in stadium construction outside of Japan. This structure is a lightweight structure in which cables are radially arranged between the inner tension ring and the outer compression ring. However, there are no cases adopted in Japan. In this paper, the authors investigate the effects of the roof configuration and initial tension on the wind response of this structure and attempt to expand the basic design data.
This paper discusses damage controlled truss beam using buckling restrained members as a force limited member. In this paper, cyclic loading tests focusing on truss beam with or without buckling restrained member and detail of joint above the buckling restrained member was conducted in order to confirm structural behavior of the truss. The findings obtained from the tests are summarized as follows: (1) the deformation capacity of truss with the buckling restrained member is superior to that without the member; (2) In the truss with buckling restrained member, bending deformation was caused on the joint above the buckling restrained member.
It is pointed out that out-of-plane buckling of buckling-restrained braces whose connections have low stiffness or strength may occur. However, the design criteria to prevent out-of-plane buckling proposed in past is based on the experiment with small out-of-plane story drift. In this paper, cyclic loading test of buckling-restrained brace under largely bidirectional story drift is conducted. Through the test, effects of stiffness and strength of the connections, and loading direction on the ultimate failure of the braces are clarified. Further, design criterion to prevent yielding splice plates is proposed and validated based on the test results.
Inter-story drifts of building frames during earthquake motions bring about compulsory deformation and possibly damage to the nonstructural exterior walls. The components such as metal skins, bolted or screwed joints and furring strips constituting the metal wall panels under such earthquake effects are treated to be series-connected in the relevant original paper, but it is pointed out in this discussion that they should be regarded parallel-connected.
The Authors are grateful for the suggestion that Prof. Hitoshi Kuwamura has graciously shared regarding the paper. In conducting research on the seismic performance of non-structural exterior walls, it is important to clarify the structural behavior of exterior walls in complicated compositions in order to ensure the safety against fall out. This paper describes the author’s response.